Kitchen hood vent duct size

[Rebel123]

Hi guys,

I would like to rough-in a hole on the side of the house for the exhaust ventilation.
Would you tell me what is the duct size to use for a kitchen hood exhaust vent that will meet the Canadian/Alberta building codes?

A young sales guy at HD said I can use 3 or 4 inch duct.
Isn't that too small?

Is it 6 inch by building codes?

Thanks.

[Xtrema]

4" is really for bathroom fans and hood fan for older homes. Hood fan now should start at 6" and up. Check the spec of the hood fan you want buy and build accordingly.

[garnet]

that's right,
bath vent duct min. 4" dia. and 6" dia. for long runs

kitchen vent duct min. 6" dia. vented to outside direct, with flapper vent of course

i like to use stainless vs aluminum for the kitchen ducting, but either will do

memory serves, code allows a max. of 300cfm fan, without need for makeup air

[Rebel123]

Very much appreciated.

Thanks.